Vacuum cleaners can include an agitator for agitating debris on a surface to be cleaned so that the debris is more easily ingested into the vacuum cleaner. In some cases, the agitator comprises a motor-driven brushroll that rotates within a base assembly or floor nozzle. Vacuum cleaners can also include a mechanism for raising or lowering the agitator relative to the surface to be cleaned, which can vary the amount of suction force applied at the surface to be cleaned.